Every time you move the block, it will register this as a successful reward, and give you the item you requested.
List of items:
CD: 0
USB: 1
DVD: 2
SD: 3 <Impossible scenario to achieve legit.
HDD: 4 <Impossible scenario to achieve legit.

You are limited to 5 items per day. It will tell you how many you have left in the DAILY REWARDS LEFT: box if you refresh the page.